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Reducing the Cost of Low-carbon Hydrogen Production via Emerging Chemical Looping Process
Jan 2023
Publication
A thorough techno-economic analysis where inherent carbon capture is examined against state-of-the-art blue hydrogen production configurations for large (100000 Nm3 /h) and very large (333000 Nm3 /h) capacities. Advanced solvent-based technologies based on post-combustion capture and auto-thermal reformer combined with a gas heated reformer are simulated with process flowsheet software and compared with the emerging chemical looping process. A network of dynamically operated packed bed reactors has been designed and modelled using an in-house code and key parameters generating uncertainties in the results have been examined in a sensitivity analysis. The chemical looping reforming process presents a higher net reforming efficiency than the benchmark cases (8.2 % higher at large scale and 1.5 % higher at very large scale) ranged 75.4–75.7 % while the specific energy for CO2 avoidance is negative in the range of − 0.78 to − 0.85 MJ/kgCO2. In the carbon capture cases the chemical looping reforming in packed beds technology generated a levelised cost of hydrogen of 168.9 £/kNm3 H2 for the large scale and 159.1 £/kNm3 H2 for the very large scale with the values for the benchmark cases being higher at 196.4 and 166.6 £/kNm3 H2 respectively while the levelised cost of hydrogen values are 1 % higher in the benchmark cases where carbon emission price is accounted for. The carbon capture ratio is 99.9 % for the chemical looping reforming cases compared to 90–91 % for the benchmark ones thus providing a significant foreground for the scale-up and implementation of chemical looping reforming technologies for hydrogen production.
Economic Dispatch Model of Nuclear High-Temperature Reactor with Hydrogen Cogeneration in Electricity Market
Dec 2021
Publication
Hydrogen produced without carbon emissions could be a useful fuel as nations look to decarbonize their electricity transport and industry sectors. Using the iodine–sulfur (IS) cycle coupled with a nuclear heat source is one method for producing hydrogen without the use of fossil fuels. An economic dispatch model was developed for a nuclear-driven IS system to determine hydrogen sale prices that would make such a system profitable. The system studied is the HTTR GT/H2 a design for power and hydrogen cogeneration at the Japan Atomic Energy Agency’s High Temperature Engineering Test Reactor. This study focuses on the development of the economic model and the role that input data plays in the final calculated values. Using a historical price duration curve shows that the levelized cost of hydrogen (LCOH) or breakeven sale price of hydrogen would need to be 98.1 JPY/m3 or greater. Synthetic time histories were also used and found the LCOH to be 67.5 JPY/m3 . The price duration input was found to have a significant effect on the LCOH. As such great care should be used in these economic dispatch analyses to select reasonable input assumptions.
R&D Status on Thermochemical IS Process for Hydrogen Production at JAEA
Nov 2012
Publication
Thermochemical hydrogen production process is one of the candidates of industrial fossil fuel free hydrogen production. Japan Atomic Energy Agency (JAEA) has been conducting R&D of the thermochemical water splitting iodine-sulfur (IS) process since the end of 1980s. This paper presents the recent study on the IS process in JAEA. In 2005-2009 test-fabrication of components collection of design database improvement of process components for higher thermal efficiency and proposition of composition measurement method were carried out. On the basis of them the integrity test of process components is carried out in 2010-2014 to examine their integrities in severe process environments. At present a Bunsen reactor which produces acids and incidental equipments has been already manufactured using corrosion resistant materials such as glass lining steel and fluoroplastic lining steel. Flow tests to examine the functionality and integrity of the materials are planned in 2012.
Incentive Structures for Power-to-X and E-fuel Pathways for Transport in EU and Member States
Jun 2022
Publication
Though Power-to-X pathways primarily Power-to-Liquids attract interest as solutions for decarbonising parts of the transport sector that are not suitable for electrification the regulatory framework until recently slowed down their implementation. This paper examines the updates in the main aspects of the legal framework in the European Union from 2019 to the beginning of 2022 related to Power-to-X: support schemes specific targets and potential barriers. The results show increasing interest and market entrance of electrolysis and push from the different actors and regulatory parties to establish solutions that will enable faster upscaling. However it is visible from the National Energy and Climate Plans and hydrogen strategies that the most emphasis is still on hydrogen as an end fuel for personal vehicles or power-to-gas. On the other hand few countries have implemented legal frameworks facilitating diverse PtX pathways without focusing solely on hydrogen. Nevertheless revisions of RED II have finally set up specific targets for electrofuels and Fit for 55 has introduced new actions supporting electrofuels in aviation and marine transport.
Hydrogen Production Possibilities in Slovak Republic
Mar 2022
Publication
Slovak Republic is a member of the European Union and is a part of the European energy market. Although Slovakia contributes only marginally to global emissions there is an effort to meet obligations from the Paris climate agreement to reduce greenhouse gases. As in many countries power industry emissions dominate Slovakia’s emissions output but are partly affected and lowered by the share of nuclear energy. The transition from fossil fuels to renewables is supported by the government and practical steps have been taken to promote the wide use of renewable resources such as biomass or solar energy. Another step in this transition process is the support of new technologies that use hydrogen as the primary energy source. The European Union widely supports this effort and is looking for possible sources for hydrogen generation. One of the main renewable resources is hydropower which is already used in the Slovak Republic. This article presents the current situation of the energy market in Slovakia and possible developments for future hydrogen generation.
Estimation of the Levelized Cost of Nuclear Hydrogen Production from Light Water Reactors in the United States
Aug 2022
Publication
In June 2021 the United States (US) Department of Energy (DOE) hosted the first-ever Hydrogen Shot Summit which lasted for two days. More than 3000 stockholders around the world were convened at the summit to discuss how low-cost clean hydrogen production would be a huge step towards solving climate change. Hydrogen is a dynamic fuel that can be used across all industrial sectors to lower the carbon intensity. By 2030 the summit hopes to have developed a means to reduce the current cost of clean hydrogen by 80%; i.e. to USD 1 per kilogram. Because of the importance of clean hydrogen towards carbon neutrality the overall DOE budget for Fiscal Year 2021 is USD 35.4 billion and the total budget for DOE hydrogen activities in Fiscal Year 2021 is USD 285 million representing 0.81% of the total DOE budget for 2021. The DOE hydrogen budget of 2021 is estimated to increase to USD 400 million in Fiscal Year 2022. The global hydrogen market is growing and the US is playing an active role in ensuring its growth. Depending on the electricity source used the electrolysis of hydrogen can have no greenhouse gas emissions. When assessing the advantages and economic viability of hydrogen production by electrolysis it is important to take into account the source of the necessary electricity as well as emissions resulting from electricity generation. In this study to evaluate the levelized cost of nuclear hydrogen production the International Atomic Energy Agency Hydrogen Economic Evaluation Program is used to model four types of LWRs: Exelon’s Nine Mile Point Nuclear Power Plant (NPP) in New York; Palo Verde NPP in Arizona; Davis-Besse NPP in Ohio; and Prairie Island NPP in Minnesota. Each of these LWRs has a different method of hydrogen production. The results show that the total cost of hydrogen production for Exelon’s Nine Mile Point NPP Palo Verde NPP Davis-Besse NPP and Prairie Island NPP was 4.85 ± 0.66 4.77 ± 1.36 3.09 ± 1.19 and 0.69 ± 0.03 USD/kg respectively. These findings show that among the nuclear reactors the cost of nuclear hydrogen production using Exelon’s Nine Mile Point NPP reactor is the highest whereas the cost of nuclear hydrogen production using the Prairie Island NPP reactor is the lowest.
Impact of Polymers on Magnesium-Based Hydrogen Storage Systems
Jun 2022
Publication
In the present scenario much importance has been provided to hydrogen energy systems (HES) in the energy sector because of their clean and green behavior during utilization. The developments of novel techniques and materials have focused on overcoming the practical difficulties in the HES (production storage and utilization). Comparatively considerable attention needs to be provided in the hydrogen storage systems (HSS) because of physical-based storage (compressed gas cold/cryo compressed and liquid) issues such as low gravimetric/volumetric density storage conditions/parameters and safety. In material-based HSS a high amount of hydrogen can be effectively stored in materials via physical or chemical bonds. In different hydride materials Mg-based hydrides (Mg–H) showed considerable benefits such as low density hydrogen uptake and reversibility. However the inferior sorption kinetics and severe oxidation/contamination at exposure to air limit its benefits. There are numerous kinds of efforts like the inclusion of catalysts that have been made for Mg–H to alter the thermodynamic-related issues. Still those efforts do not overcome the oxidation/contamination-related issues. The developments of Mg–H encapsulated by gas-selective polymers can effectively and positively influence hydrogen sorption kinetics and prevent the Mg–H from contaminating (air and moisture). In this review the impact of different polymers (carboxymethyl cellulose polystyrene polyimide polypyrrole polyvinylpyrrolidone polyvinylidene fluoride polymethylpentene and poly(methyl methacrylate)) with Mg–H systems has been systematically reviewed. In polymer-encapsulated Mg–H the polymers act as a barrier for the reaction between Mg–H and O2/H2O selectively allowing the H2 gas and preventing the aggregation of hydride nanoparticles. Thus the H2 uptake amount and sorption kinetics improved considerably in Mg–H.
Effect of Flow Speed on Ignition Characteristics of Hydrogen/air Mixtures
Sep 2021
Publication
A fuel cell vehicle has a purging system for exhausting contaminated hydrogen gas. Notwithstanding the allowable hydrogen emissions levels in the purging system are regulated by the GTR a further research on the safety requirement of emissions concentrations is therefore needed for the vehicle design into a more rational system. In the present study the effects of flow speed concentration humidity on ignition characteristics of hydrogen/air mixtures were experimentally investigated. The results demonstrate that the value of Lower Flammable Limit increased with an increase in the velocity of hydrogen/air mixtures and slightly increased with a decrease in oxygen concentration.
Fostering Macroeconomic Research on Hydrogen-Powered Aviation: A Systematic Literature Review on General Equilibrium Models
Feb 2023
Publication
Hydrogen is a promising fuel to decarbonize aviation but macroeconomic studies are currently missing. Computable general equilibrium (CGE) models are suitable to conduct macroeconomic analyses and are frequently employed in hydrogen and aviation research. The main objective of this paper is to investigate existing CGE studies related to (a) hydrogen and (b) aviation to derive a macroeconomic research agenda for hydrogen-powered aviation. Therefore the well-established method of systematic literature review is conducted. First we provide an overview of 18 hydrogen-related and 27 aviation-related CGE studies and analyze the literature with respect to appropriate categories. Second we highlight key insights and identify research gaps for both the hydrogen and aviation-related CGE literature. Our findings comprise inter alia hydrogen’s current lack of cost competitiveness and the macroeconomic relevance of air transportation. Research gaps include among others a stronger focus on sustainable hydrogen and a more holistic perspective on the air transportation system. Third we derive implications for macroeconomic research on hydrogen-powered aviation including (I) the consideration of existing modeling approaches (II) the utilization of interdisciplinary data and scenarios (III) geographical suitability (IV) the application of diverse policy tools and (V) a holistic perspective. Our work contributes a meaningful foundation for macroeconomic studies on hydrogen-powered aviation. Moreover we recommend policymakers to address the macroeconomic perspectives of hydrogen use in air transportation.
Cost Assessment of Alternative Fuels for Maritime Transportation in Ireland
Aug 2022
Publication
In this study we investigated the cost-effectiveness of four alternatives: Liquified Natural Gas (LNG) methanol green hydrogen and green ammonia for the case of top 20 most frequently calling ships to Irish ports in 2019 through the Net Present Value (NPV) methodology incorporating the benefits incurred through saved external carbon tax and conventional fuel costs. LNG had the highest NPV (€6166 million) followed by methanol (€1705 million) and green hydrogen (€319 million). Green ammonia utilisation (as a hydrogen carrier) looks inviable due to higher operational costs resulting from its excessive consumption (i.e. losses) during the cracking and purifying processes and its lower net calorific value. Green hydrogen remains the best option to meet future decarbonisation targets although a further reduction in its current fuel price (by 60%) or a significant increment in the proposed carbon tax rate (by 275%) will be required to improve its cost-competitiveness over LNG and methanol.
The Economics and the Environmental Benignity of Different Colors of Hydrogen
Feb 2022
Publication
Due to the increasing greenhouse gas emissions as well as due to the rapidly increasing use of renewable energy sources in the electricity generation over the last years interest in hydrogen is rising again. Hydrogen can be used as a storage for renewable energy balancing the whole energy systems and contributing to the decarbonization of the energy system especially of the industry and the transport sector. The major objective of this paper is to discuss various ways of hydrogen production depending on the primary energy sources used. Moreover the economic and environmental performance of three major hydrogen colors as well as major barriers for faster deployment in fuel cell vehicles are analyzed. The major conclusion is that the full environmental benefits of hydrogen use are highly dependent on the hydrogen production methods and primary sources used. Only green hydrogen with electricity from wind PV and hydro has truly low emissions. All other sources like blue hydrogen with CCUS or electrolysis using the electricity grid have substantially higher emissions coming close to grey hydrogen production. Another conclusion is that it is important to introduce an international market for hydrogen to lower costs and to produce hydrogen where conditions are best. Finally the major open question remaining is whether e including all external costs of all energy carriers hydrogen of any color may become economically competitive in any sector of the energy system. The future success of hydrogen is very dependent on technological development and resulting cost reductions as well as on future priorities and the corresponding policy framework. The policy framework should support the shift from grey to green hydrogen.
Experimental Study on Flame Characteristics of Cryogenic Hydrogen Jet Fire
Sep 2021
Publication
In this work cryogenic hydrogen fires at fixed pressures and various initial temperatures were investigated experimentally. Flame length width heat fluxes and temperatures in down-stream regions were measured for the scenarios with 1.6-3 mm jet nozzle 106 to 273 K 2-5 barabs. The results show that the flame size is related to not only the jet nozzle diameter but also the release pressure and initial temperature. The correlations of normalized flame length and width are proposed with the stagnation pressure and the ratio of ambient and stagnation temperatures. Under constant pressure the flame size total radiative power and radiation fraction increase with the decrease of temperature due to lower choked flow velocity and higher density of cryogenic hydrogen. The correlation of radiation fraction proposed by Molina et al. at room temperature is not suitable to predict the cryogenic hydrogen jet fires. Based on piecewise polynomial law
Sizing and Performance Analysis of Hydrogen- and Battery-Based Powertrains, Integrated into a Passenger Train for a Regional Track, Located in Calabria (Italy)
Aug 2022
Publication
In order to decarbonize the rail industry the development of innovative locomotives with the ability to use multiple energy sources constituting hybrid powertrains plays a central role in transitioning from conventional diesel trains. In this paper four configurations based on suitable combinations of fuel cells and/or batteries are designed to replace or supplement a diesel/overhead line powertrain on a real passenger train (the Hitachi Blues) tested on an existing regional track the Catanzaro Lido–Reggio Calabria line (Italy) managed by Trenitalia SpA. (Italy). The configurations (namely battery–electrified line full-battery fuel cell–battery–electrified line and fuel cell–battery) are first sized with the intention of completing a round trip then integrated on board with diesel engine replacement in mind and finally occupy a portion of the passenger area within two locomotives. The achieved performance is thoroughly examined in terms of fuel cell efficiency (greater than 47%) hydrogen consumption (less than 72 kg) braking energy recovery (approximately 300 kWh) and battery interval SOC.
Simulation of Hydrogen Mixing and Par Operation During Accidental Release in an LH2 Carrier Engine Room
Sep 2021
Publication
Next-generation LH2 carriers may use the boil-off gas from the cargo tanks as additional fuel for the engine. As a consequence hydrogen pipes will enter the room of the ship’s propulsion system and transport hydrogen to the main engine. The hydrogen distribution resulting from a postulated hydrogen leak inside the room of the propulsion system has been analyzed by means of Computational Fluid Dynamics (CFD). In a subsequent step simulations with passive auto-catalytic recombiners (PARs) were carried out in order to investigate if the recombiners can increase the safety margins during such accident scenarios. CFD enables a 3D prediction of the transient distribution with a high resolution allowing to identify local accumulation of hydrogen and consequently to identify optimal PAR positions as well as to demonstrate the efficiency of the PARs. The simulation of the unmitigated reference case reveals a strong natural circulation driven by the density difference of hydrogen and the incoming cold air from the ventilation system. Globally this natural circulation dilutes the hydrogen and removes a considerable amount from the room of the ship’s propulsion system via the ventilation ducts. However a hydrogen accumulation beyond the flammability limit is identified below the first ceiling above the leak position and the back-side wall of the engine room. Based on these findings suitable positions for recombiners were identified. The design objectives of the PAR system were on the one hand to provide both high instantaneous and integral removal rate and on the other hand to limit build-up of flammable clouds by means of depletion and PAR induced mixing processes. The simulations performed with three different PAR arrangements (variation of large and<br/>small PAR units at different positions) confirm that the PARs reduce efficiently the hydrogen<br/>accumulations.
A Review of Projected Power-to-Gas Deployment Scenarios
Jul 2018
Publication
Technical economic and environmental assessments of projected power-to-gas (PtG) deployment scenarios at distributed- to national-scale are reviewed as well as their extensions to nuclear-assisted renewable hydrogen. Their collective research trends outcomes challenges and limitations are highlighted leading to suggested future work areas. These studies have focused on the conversion of excess wind and solar photovoltaic electricity in European-based energy systems using low-temperature electrolysis technologies. Synthetic natural gas either solely or with hydrogen has been the most frequent PtG product. However the spectrum of possible deployment scenarios has been incompletely explored to date in terms of geographical/sectorial application environment electricity generation technology and PtG processes products and their end-uses to meet a given energy system demand portfolio. Suggested areas of focus include PtG deployment scenarios: (i) incorporating concentrated solar- and/or hybrid renewable generation technologies; (ii) for energy systems facing high cooling and/or water desalination/treatment demands; (iii) employing high-temperature and/or hybrid hydrogen production processes; and (iv) involving PtG material/energy integrations with other installations/sectors. In terms of PtG deployment simulation suggested areas include the use of dynamic and load/utilization factor-dependent performance characteristics dynamic commodity prices more systematic comparisons between power-to-what potential deployment options and between product end-uses more holistic performance criteria and formal optimizations.
Fuel Flexibility of Solid Oxide Fuel Cells
Aug 2021
Publication
One of the major advantages of SOFCs is their high fuel flexibility. Next to natural gas and hydrogen which are today’s most common fuels for SOFC-systems and cell-/stack-testing respectively various other fuels are applicable as well. In the literature a number of promising results show that available fuels as propane butane ammonia gasoline diesel etc. can be applied. Here the performance of an anode supported cell operated in specialized single cell test benches with different gaseous and liquid fuels and reformates thereof is presented. Fuels as ammonia dissolved urea (AddBlueTM) methane/steam and ethanol/water mixtures can directly be fed to the cell whereas propane and diesel require external reforming. It is shown that in case of a stable fuel supply the cell performance with such fuels is similar to that of appropriate mixtures of H2 N2 CO CO2 and steam if the impact of endothermic reforming or decomposition reactions is considered. Even though a stable fuel cell operation with such fuels is possible in a single cell test bench it should be pointed out that an appropriate fuel processing will be mandatory on the system level.
Techno-Economic Analysis of Hydrogen Storage Technologies for Railway Engineering: A Review
Sep 2022
Publication
According to the specific requirements of railway engineering a techno-economic comparison for onboard hydrogen storage technologies is conducted to discuss their feasibility and potentials for hydrogen-powered hybrid trains. Physical storage methods including compressed hydrogen (CH2 ) liquid hydrogen (LH2 ) and cryo-compressed hydrogen (CcH2 ) and material-based (chemical) storage methods such as ammonia liquid organic hydrogen carriages (LOHCs) and metal hydrides are carefully discussed in terms of their operational conditions energy capacity and economic costs. CH2 technology is the most mature now but its storage density cannot reach the final target which is the same problem for intermetallic compounds. In contrast LH2 CcH2 and complex hydrides are attractive for their high storage density. Nevertheless the harsh working conditions of complex hydrides hinder their vehicular application. Ammonia has advantages in energy capacity utilisation efficiency and cost especially being directly utilised by fuel cells. LOHCs are now considered as a potential candidate for hydrogen transport. Simplifying the dehydrogenation process is the important prerequisite for its vehicular employment. Recently increasing novel hydrogen-powered trains based on different hydrogen storage routes are being tested and optimised across the world. It can be forecasted that hydrogen energy will be a significant booster to railway decarbonisation.
Effect of Mechanical Ventilation on Accidental Hydrogen Releases - Large Scale Experiments
Sep 2021
Publication
This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces like underground garages. The purpose was to find the mass flow rate limit hence the TPRD diameter limit that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard outlet 315 mm diameter. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzle from different hydrogen reservoir pressures. Both types of mass flow: constant and blowdown were included in the experimental matrix. The analysis of hydrogen concentration of created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.
Projecting the Future Cost of PEM and Alkaline Water Electrolysers; a CAPEX Model Including Electrolyser Plant Size and Technology Department
Oct 2022
Publication
The investment costs of water electrolysis represent one key challenge for the realisation of renewable hydrogen-based energy systems. This work presents a technology cost assessment and outlook towards 2030 for alkaline electrolysers (AEL) and PEM electrolysers (PEMEL) in the MW to GW range taking into consideration the effects of plant size and expected technology developments. Critical selected data was fitted to a modified power law to describe the cost of an electrolyser plant based on the overall capacity and a learning/technology development rate to derive cost estimations for different PEMEL and AEL plant capacities towards 2030. The analysis predicts that the CAPEX gap between AEL and PEMEL technologies will decrease significantly towards 2030 with plant size until 1 e10 MW range. Beyond this only marginal cost reductions can be expected with CAPEX values approaching 320e400 $/kW for large scale (greater than 100 MW) plants by 2030 with subsequent cost reductions possible. Learning rates for electrolysers were estimated at 25 e30% for both AEL and PEMEL which are significantly higher than the learning rates reported in previous literature.
Designing Hydrogen Recirculation Ejectors for Proton Exchange Membrane Fuel Cell Systems
Jan 2023
Publication
The proton exchange membrane fuel cell (PEMFC) is a promising device in the fields of power generation energy storage aerospace and public transportation. The hydrogen recirculation ejector with the advantages of low cost high durability and no parasitic power is the key component of PEMFC systems. However it is challenging to design a hydrogen recirculation ejector to cover the wide operating conditions of PEMFC systems. In order to design an ejector for fuel cell systems a comprehensive understanding of ejector research is required. Consequently the state-of-the-art research work on the hydrogen recirculation ejector is analyzed including characteristics of the ejector in PEM fuel cell systems geometry design and optimization different types of ejectors and a comparison between them and system integration and control. Through a comprehensive analysis of ejectors further research suggestions on designing high-performance ejectors are presented.
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